The specs look good. If it were me, though, I would steer clear of the machine for four reasons:
1. Small form factor PC's like this can be hard, if not impossible, to upgrade. You'll never be able to add another internal hard drive to this machine or increase its RAM, and it's pretty unlikely you'd be able to change the video cards.
2. The PCI-E slots are only x8. The standard is x16. That means right away that your graphics processing speed effectively will be cut in half, as the socket will be a bottleneck. Further, all the slots in the machine are "mini socket" slots, meaning they won't take standard sized cards. It will be difficult and expensive to find anything that can go in those slots, should you ever wish to expand the machine's capabilities.
3. The GeForce 9800S is kind of an oddball. It was totally unheard of before the Firebird, and I think HP is still the only one using it. It's somewhere in between a desktop card and a mobile card. The positive sales-pitch description of it is that it's smaller and uses less power than a desktop card, but performs better than a mobile card. The obvious, equally true, reverse side of that coin is that it performs worse than a normal desktop card, but is stuck in a machine that is not portable like a laptop would be. To me, sacrificing power without gaining portability is a lose-lose any way you look at it.
4. The machine is overpriced for the specs it offers. You're basically paying laptop prices, but not getting the portability to justify such higher costs. In that same $1300 range, you could get a much more powerful, far more expandable, machine, with a normal sized case.
Here are a few examples:
http://www.newegg.com/Product/Product.aspx?Item=N82E16883227135 ($20 cheaper, better CPU, double the L2 cache, double the memory, double the hard drive size, significantly better video card, tons more expansion capability, standard expansion slots for compatibility with standard components)
http://www.newegg.com/Product/Product.aspx?Item=N82E16883229083 ($300 cheaper, way better CPU, 50% bigger L2 cache, tri-channel memory, 50% more memory, much better video card, tons more expansion capability, standard expansion slots for compatibility with standard components)
http://www.newegg.com/Product/Product.aspx?Item=N82E16883229054 ($70 cheaper, better CPU, double the L2 cache, double the memory, 50% bigger hard drive, two optical drives, significantly better video card, better card reader, tons more expansion capability, standard expansion slots for compatibility with standard components)
Those are just a few I found with a really quick search of just one website. If you were to shop around more thoroughly, I'm sure there are even better deals to be had. Or you can go for the best deal of all, which is to buy parts, and put the computer together yourself. It's easier than you might think.
The ONLY reason to get that Firefbird would be if you're absolutely so in love with the looks of that funky little case it comes in that you couldn't possibly bring yourself to live without it. Otherwise, even the ugliest case in the world can just be put under the desk and forgotten about. Not that it necessarily has to be a choice, since normal sized cases can be attractive, but if it has to come down to one or the other, I'd much rather spend the same money on capabilities over aesthetics.